Medical Author: Benjamin C. Wedro, MD, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD
A 73 year old woman is vacuuming when her left leg becomes weak and she has difficulty standing. Her face and left arm become numb. She calls for her husband, who helps her to a chair, and even though the symptoms resolve within five minutes, they decide to go to the hospital. In the hospital parking lot, they debate whether they should go into the Emergency Department or just turn around and go home.
This woman has suffered a TIA, or transient ischemic attack, which is basically a stroke that resolves on its own. Since the right side of the brain controls the left side of the body (and vice versa), she suffered reversible damage to her right brain and that caused her left leg to get weak and also developed numbness on the left side.
After some discussion, the woman decides she wants to seek medical care, and she and her husband walk through the Emergency Department doors. The doctor and nurse take a medical history to find out what happened. All of the symptoms have resolved, so the next step is follow-up care. The healthcare team asks the patient if she has any of the known risk factors for stroke (which are the same for heart disease):
The doctor advises the woman that there is a need to rush to medical care because if the symptoms do not resolve, there is a very narrow window of time to use alteplase (Activase, TPA), a clot busting drug, to reverse the stroke. Within three hours of the onset of stroke symptoms, the patient needs to get to the hospital, have the initial diagnosis made, have blood tests drawn, a CT scan done to insure that bleeding is not the cause of the stroke, a neurologist needs to be consulted, and the drug given. The earlier the patient is given TPA for stroke, the better the potential outcome and the lower the risk of complications.
A TIA is a stroke that resolves. Most symptoms get better on their own within minutes, but by definition, it may take up to 24 hours for the neurologic deficits to resolve. Because there is no way of knowing when a stroke begins, or whether it will resolve on its own, the EMS system (Emergency Medical Services) or 911 needs to be activated at the first sign of stroke. These symptoms of stroke include:
- weakness or paralysis on one side of the body,
- speech or vision difficulties and
- due to circulation problems at the base of the brain, loss of coordination and balance and falling without notice.
Unfortunately, many patients do not qualify for TPA because they or their family do not recognize the symptoms of stroke and wait too long at home. The three hour window is very narrow. In some large hospitals, the window can be extended a couple of additional hours, if the hospital has the capability of injecting the drug directly into the blocked artery in the brain. This requires both a radiologist with special skills to thread a catheter or tube into the brain blood vessels and a hospital with the necessary equipment to do the procedure.
The woman and her husband are reassured after the physical examination that all is well, but the doctor wants to do some testing. And electrocardiogram (EKG) is performed to confirm normal heart rhythms and a CT scan of the brain is done, since small areas of bleeding can also cause stroke and TIA. After these results return as normal, a carotid ultrasound is obtained to ensure that there is no critical narrowing of the carotid artery, which would require surgery.
The doctor sits at the bedside with the woman and her husband and is pleased to tell them that the tests are normal. But plenty of time is spent discussing the potential risks for having a future stroke. While this time, the symptoms resolved, there is no guarantee that future episodes will get better.
TIA is diagnosed first by physical examination of the patient, including a full neurologic examination. This may include:
Assessing whether the patient is alert and oriented.
- Checking vision and eye movements.
- Looking for weakness in facial muscles.
- Testing power and sensation of all extremities.
- Looking for alteration in balance and coordination.
- Checking speech, recognition, and reading.
In most Emergency Departments, if there is concern for continued stroke symptoms, a standardized assessment will be done, often using the National Institute of Health Stroke Scale.
The doctor also may listen to the neck for bruits, or abnormal sounds, made by narrowing of the carotid arteries causing decreased blood flow. The heart is often checked to look for the irregular pulse of atrial fibrillation. The rest of the physical examination is performed to look for other medical conditions that may contribute to a stroke or TIA.
What is the treatment for a TIA?
The woman and her husband are worried that another TIA will occur, and the doctor advises them that the initial treatment is to take an aspirin a day. The doctor reminds the couple that the risk of stroke in the next few weeks is high and that they should not hesitate to come in at any time for care and evaluation. They should think of a TIA as angina of the brain, in which it is a warning sign of an impending closure of a blood vessel and should not be ignored or taken lightly. The doctor reminds them that taking steps to minimize risk factors for stroke will make a big difference.
Prevention is the best way to treat heart and brain blood vessel narrowing. That includes minimizing the risks as listed above. Aspirin is the drug of choice for TIA prevention, by making platelets less sticky and less prone to get stuck in the narrowed blood vessels of the brain. Those who suffer a TIA while taking aspirin will be offered another type of antiplatelet drug like clopidogrel bisulfate (Plavix) or aspirin/dipyridamole ER (Aggrenox).
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What is the prognosis for TIA?
Unfortunately, the risk of stroke after TIA is very high. Ten percent of people with TIAs will have a stroke within three months. The purpose of accessing medical care is to help minimize risk factors to help decrease that 10% risk. Studies published in 2007 suggested that if blood pressure is tightly controlled, cholesterol levels brought down with medication, and smoking cessation is begun, the risk of future stroke can be cut to 2%.